Mattress

A mattress, comprising:

• a movable part, comprising a rotatably movable plate and an actuator for rotating the movable plate, wherein the actuator comprises a first inflatable/contractible bag that is inflatable and contractible through supplying or exhausting of gas, and the movable plate is configured to adjust a rotation angle through supplying or exhausting of the gas to and from the first inflatable/contractible bag;
• a mattress body, comprising a first mattress part disposed above the movable part, and a second mattress part provided separately from the first mattress part and disposed to surround the first mattress part in a plan view;
• an angle sensor for measuring the rotation angle of the movable plate;
• and
• a control part for controlling the supplying and exhausting of the gas to and from the first inflatable/contractible bag,
• wherein the control part is configured to control the supplying and exhausting of the gas to and from the first inflatable/contractible bag based on the angle measured by the angle sensor,
• wherein the first mattress part is configured to be rotated upward about a predetermined rotation axis by the movable part,
• wherein the movable plate has a shape having a lateral direction and a longitudinal direction, and the movable plate has at least one rotation center axis tilted with respect to a center line that extends in the longitudinal direction and passes through a center of the movable plate in the lateral direction in the plan view,
• wherein the at least one rotation center axis is tilted at an angle with respect to the center line, the angle is more than 0 degree and is less than 90 degrees, and the at least one rotation center axis passes through the center line at the angle,
• wherein the mattress body has a rectangular shape having a short side along a lateral direction and a long side along a longitudinal direction, and the first mattress part has a shape having a lateral direction and a longitudinal direction, wherein the first mattress part has a first side and a second side parallel and opposite to each other along the lateral direction, the length of the first side is greater than the length of the second side, the first side is located on the short side of the mattress body, and an orthogonal projection of the at least one rotation center axis of the movable plate on the first mattress part passes through an orthogonal projection of the second side on the first mattress part.